Laboratory clopidogrel resistance is associated with adverse atherothrombotic events in patients with coronary artery disease. In the proposed study we wish to prospectively assess the effect of reloading with 600 mg clopidogrel, and administer maintenance treatment with clopidogrel 150 mg/day for one month in a group of acute myocardial infarction (AMI) patients who demonstrate non-responsiveness to clopidogrel.